function extra_options(active, collectieids){
                  
    collection = collectieids.split("|");
    
    for(i=0; i<collection.length; i++){
        
        if(typeof(document.getElementById("extra_opties_"+collection[i])) != "undefined"){
            document.getElementById("extra_opties_"+collection[i]).style.display = "none";
        }
    }
    
    if(active != 0){
        
        if(typeof(document.getElementById("extra_opties_"+active)) != "undefined"){
            document.getElementById("extra_opties_"+active).style.display = "block";
        }
    }
}